From cea394772d3c41d04cb71a032f6ed878392bd134 Mon Sep 17 00:00:00 2001
From: Vladimir Murzin <vladimir.murzin@arm.com>
Date: Mon, 18 Jun 2018 14:33:03 +0100
Subject: [PATCH] ARM: 8775/1: NOMMU: Use instr_sync instead of plain isb in
common code
Greg reported that commit 3c24121039c9d ("ARM: 8756/1: NOMMU: Postpone
MPU activation till __after_proc_init") is causing breakage for the
old Versatile platform in no-MMU mode (with out-of-tree patches):
AS arch/arm/kernel/head-nommu.o
arch/arm/kernel/head-nommu.S: Assembler messages:
arch/arm/kernel/head-nommu.S:180: Error: selected processor does not support `isb' in ARM mode
scripts/Makefile.build:417: recipe for target 'arch/arm/kernel/head-nommu.o' failed
make[2]: *** [arch/arm/kernel/head-nommu.o] Error 1
Makefile:1034: recipe for target 'arch/arm/kernel' failed
make[1]: *** [arch/arm/kernel] Error 2
Since the code is common for all NOMMU builds usage of the isb was a
bad idea (please, note that isb also used in MPU related code which is
fine because MPU has dependency on CPU_V7/CPU_V7M), instead use more
robust instr_sync assembler macro.
Fixes: 3c24121039c9 ("ARM: 8756/1: NOMMU: Postpone MPU activation till __after_proc_init")
Reported-by: Greg Ungerer <gerg@kernel.org>
Tested-by: Greg Ungerer <gerg@kernel.org>
Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
---
arch/arm/kernel/head-nommu.S | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm/kernel/head-nommu.S b/arch/arm/kernel/head-nommu.S
index dd546d65a3830..7a9b86978ee1e 100644
--- a/arch/arm/kernel/head-nommu.S
+++ b/arch/arm/kernel/head-nommu.S
@@ -177,7 +177,7 @@ M_CLASS(streq r3, [r12, #PMSAv8_MAIR1])
bic r0, r0, #CR_I
#endif
mcr p15, 0, r0, c1, c0, 0 @ write control reg
- isb
+ instr_sync
#elif defined (CONFIG_CPU_V7M)
#ifdef CONFIG_ARM_MPU
ldreq r3, [r12, MPU_CTRL]
--
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